,The Power Train 传动系统,Unit 5,Passage A,Two functions,Transmits power from engine to the drive shaft / wheels Varies the amount of torque,Passage A,Power Train (),Passage A,Power Train (),Passage A,Includes:,Engines: SI or CI engine Transmission: Manual or Automatic Clutch: on manual transmission, or torque converter on automatic transmission Drive shaft: transmits the power from the transmission to the differential Differential: carries the power to two wheel axles.,Passage A,Manual Transmission,Passage A,Gears inside the transmission change the cars drive-wheel speed and torque in relation to engine speed and torque, which keeps the engines output matched as closed as possible to varying road speeds and loads. Manual transmission requires a clutch to apply and remove engine torque to the input shaft of the transmission. Manual transmission usually has four or five speeds, and often has “overdrive”, which means that the output shaft can turn faster than the input shaft for fuel economy on the highway.,Passage A,Clutch,Passage A,The clutch allows engine power to be applied gradually when a vehicle is starting out, and interrupts power to avoid gear crunching when shifting. Engaging and Disengaging. Basic components are: the flywheel, clutch disc, pressure plate, releasing bearing and linkage.,Passage A,Clutch,Passage A,Clutch disc,Basically a steel plate, covered by frictional material Whats the function of middle spring in clutch disc? Decrease the torsional vibration,Passage A,Release bearing and Linkage,Passage A,Release bearing:,The throw-out bearing moves toward the flywheel, pushing in the pressure plates fingers and moving the pressure plate fingers or levers against pressure plate spring force.,Release bearing:,The throw-out bearing moves toward the flywheel, pushing in the pressure plates fingers and moving the pressure plate fingers or levers against pressure plate spring force.,Linkage:,Transmits and multiplies the drivers leg force to the fork of clutch pressure plate. Mechanical clutch and Hydraulic clutch.,Passage A,Automatic transmission,Passage A,The key difference between a manual and an automatic transmission is that the first one locks and unlocks different set of gears to the output shaft to achieve the various gear ratios, while the second one uses the planetary gear set to produce all of the different gear ratios. Receives the engine power through a torque converter, rather than the clutch, both of them are drived by the engines crankshaft.,Passage A,New words （生词）,Converter Differential Axle Transaxle Depress Interrupt Crunch Linkage Frictional Squeeze,Achieve Planetary Component Gearshift Deceleration Set of gear Final drive Thrust ring Up / down shift Release lever,Passage B,Power Train (),Takes the place of (Substitutes) the clutch to send the power from the engine to the transmission input shaft. Offers the advantage of multiplying and turning power provided by the engine. Three parts: Impeller, Turbine, Stator(Guid wheel),Torque converter,Passage B,Power Train (),It is filled with transmission fluid, which is moved by impeller blades. The stators vanes catch the oil thrown off from the impeller, and use it to move the turbines blades. When the impeller spins above a certain speed, the turbine spins, driven by the impeller.,Torque converter (),Passage B,Power Train (),Provides for the different gear ratios needed. A planetary gear set consists of a sun gear, planet gears, and a internal ring gear.,Planetary gearing,The planet gears are mounted and surported by the planet carrier and each gear spins on its own separate shaft. The gears are constantly meshed with sun and ring gears.,Passage B,Power Train (),Final drive system. When a car is moving straight ahead, both wheels are free to rotate. Drive pinion rotates the differential ring gear, beveled pinion gears are carried around by ring gear and rotate as one unit, then the final power is transmitted from the pinion gears to the wheel shaft. Each axle receives the same power, each wheel turns at the same speed.,Differential,Passage B,Power Train (),When a car is turns a sharp corner, only one wheel rotates freely. Torque will be produced to make the pinion gears rotate on their own axis and walk around their gears. Then, the different rotating velocity on different shaft is allowed by the differential unit.,Differential,Passage B,Power Train (),Universal joint (U joint) Allows the drive shaft to move up and down, to allow for suspension travel. Some drive shafts also have a slip joint that allows the drive shaft to make minor length changes as the vehicle suspension height changes.,Drive shaft,http:/www.automotive-,http:/jeep.zerok.ru/index.php?page=86,Passage B,New words （生词）,Multiply Impeller Turbine Stator Blade Vane Beveled Stationary Propeller Suspension Slip,Planet carrier Constant mesh Transaxle assembly Rear axle assembly Differential case Pinion gear Universal joint Suspension tra